An injection is used as an option for pain treatment for some patients. It is used in the treatment of pain in muscle areas that contain trigger points as well as muscles where knots have formed and the muscle is not able to relax. The knots can often be felt under ones skin. The injection is placed into the trigger point directly. This treatment is helpful in conditions such as myofascial pain syndrome, tension headaches, fibromyalgia, along with other conditions. The injection may contain bupivicaine, lidocaine, an anesthetics mixture, or a corticosteroid that may be mixed with lidocaine or given alone.